The present invention relates to the field of surgery. The invention has particular utility in connection with the removal and collection of bone from the surface of one or more donor sites, and the preparation and placement of the autogenous bone material at a second location in the patient, e.g. for use in grafting bone to osseous deficiencies, such as periodontal and dentoalveolar defects, bone deficiencies around dental implants, and numerous orthopedic applications that require grafting, and will be described in connection with such utility, although other utilities are contemplated.
Many reconstructive procedures used in medicine and dentistry involve the manipulation and healing of bones. Such procedures may involve changes in the position, orientation, shape and size of skeletal structures. A problem that is commonly encountered during such procedures is a lack of bone graft material. Bone graft material may be used in several applications, such as to fill between sections of bone that have been repositioned, to change surface geometry, or to add bone to an area that is deficient, such as in conjunction with periodontal surgery or dental implants in the patients"" jaws.
The need to harvest small bone grafts from intraoral sites has been common in periodontal surgery to restore bone defects around teeth. In the case of dental implant surgery, bone grafts may be needed to augment atrophic alveolar ridges of the maxilla and/or mandible and the sinus floor to increase the dimension of these bone sites to accommodate and totally cover the endosseus portion of implant fixtures. Bone grafts also are used in conjunction with guided tissue regeneration; a technique that uses a membrane to isolate hard tissue from soft tissue sites and potentiates hard tissue healing.
It is often difficult to harvest adequate amounts of autogenous bone from intraoral sites. Therefore, clinicians often rely on non-autogenous sources of graft material, such as bone from cadaver sources (homologous or allogenic grafts), animal sources (heterogenous or xenogeneic grafts), or synthetic bone substitutes. However, healing of non-autogenous material grafts is not as extensive or predictable as healing of autogenous bone; plus there is the additional cost of such non-autogenous graft materials, which can be significant.
Clinicians use several techniques to remove bone for grafting for intraoral procedures. In one such technique rotary instruments, such as side cutting burrs or trephines, are used to remove a piece or section of cortical bone from a local intraoral site in the maxilla or mandible. The cortical bone is often morsalized into a particulate form, either manually with a rongeur like instrument or in a bone mill. The particulate bone is then combined with blood to form an osseous coagulum, which is then positioned and packed into the osseous defect around the teeth or implant. See Robinson, R.E. xe2x80x9cOsseous Coagulum for Bone Inductionxe2x80x9d, J. Periodontology 40:503(1969). Suction devices with filters have been fabricated and manufactured to collect the bone dust from rotary instruments. See Hutchinson, RA xe2x80x9cUtilization of an Osseous Coagulum Collection Filterxe2x80x9d, J. Periodontology 44:668(1973). See also Goldman, et al., xe2x80x9cPeriodontal Therapyxe2x80x9d, pp 994-1005, C.V. Mosby Co., (1980); and Haggarty, et al., xe2x80x9cAutogenous Bone Grafts: A Revolution in the Treatment of Vertical Bone Defectsxe2x80x9d, J. Periodontology 42:626(1971). While such techniques are widely used by clinicians, the techniques have limitations, since sites to harvest sections of intraoral bone are limited in number and extent because of limited intraoral access, proximity to tooth roots, nerve structures and sinus cavities, and thin plates of bone.
Other techniques for harvesting bone include using chisels or osteotomes to remove and manually collect shavings from the surface. These instruments must be very sharp and the process is often awkward and time consuming. Other manual instruments such as bone files and rasps also remove bone. However, the efficiency of cutting and the ability to use the removed bone is greatly limited. Another technique is to collect bone dust generated by twist drills or taps used to prepare the sites for implant placement. However, much of the bone material may be lost while the site is being irrigated to cool the cutting instrument. When larger amounts of bone are needed for major reconstructive procedures, other sites such as the hip (anterior or posterior ilium), tibia, ribs, or the calvarium often are used. However, using such other sites necessitates a second surgical site, which may require postoperative hospitalization, and thus is less amenable, e.g. in the case of an out-patient dental procedure.
Various surgical devices have been proposed and/or are in use to harvest bone marrow samples for biopsy or devices such as rongeurs or bone cutters or punches to remove sections or convex edges of bone. Surgical devices also are in use in arthroscopy and endoscopy for cutting or drilling bone or tissue and removing the tissue fragments. Ultrasonic devices to cut bone also are in use; however, such devices require the removal of the irrigant and debris liberated by the apparatus. Each of these methods and/or devices, however, suffers from one or more deficiencies as applied to the collection of bone for grafting.
Yet other patented devices have been proposed; each of these, however, suffers from one or more deficiencies:
U.S. Pat. Nos. 5,403,317 and 5,269,785 to Bonutti show a method and apparatus for the percutaneous cutting and removal of tissue fragments from human. The Bonutti device removes the tissue fragments by suction where it can be collected and then placed elsewhere in the patient from where originally obtained. Bonutti employs a flexible drill, and suction to remove the debris to an externally placed collection reservoir, where it is compressed before being replaced into the patient.
U.S. Pat. No. 2,526,662 to Hipps discloses a bone meal extractor apparatus for mechanically removing bone meal from a donor bone site through a small percutaneous site using a drill. The drill shavings, which comprise primarily sub-surface bone, are then evacuated into an open cut that the drill passes through, for collection.
U.S. Pat. No. 4,798,213 to Doppelt teaches a device for obtaining a bone biopsy for diagnosis of various bone diseases. The Doppelt device is intended to remove a core of bone using a tubular drill, while maintaining the architecture of the tissue. The sample is obtained from the marrow space and not intended from re-implantation.
U.S. Pat. No. 5,133,359 to Kedem shows a hard tissue biopsy instrument in which samples are taken using a rotatably driven hollow needle.
U.S. Pat. No. 4,366,822 to Altshuler discloses a method and apparatus for bone marrow cell separation and analysis. The Altshuler apparatus collects bone marrow cells in a filtration chamber on a filter interposed between a needle directed into the bone marrow site and an aspirator or vacuum source, i.e. using negative pressure to withdrawal marrow cells through a needle.
U.S. Pat. No. 5,052,411 to Schoolman teaches, a vacuum barrier attachment for shielding the operator of a medical tool from harmful aerosols and blood, etc. created by drilling, sawing types of actions, etc. The Schoolman device requires vacuum and is not intended for harvesting tissue for re-implantation.
U.S. Pat. No. 4,722,338 to Wright et al. discloses a device instrument for removing bone that uses a shearing action similar to a rongeur to cut bone, with means for collecting fragments of bone as they are removed. The Wright et al. device reportedly is used mainly for the removal of projections or edges of bone using a shearing mechanism without the intent of harvesting the bone for grafting.
U.S. Pat. No. 4,994,024 to Falk teaches an arthroscopy hook-clippers device that allows the unobstructed removal of tissue or bone with removal of the fragments by suction. The Falk device is intended for arthroscopy applications and with the removal of projections of tissue or bone and not specifically for the harvest of tissue for grafting.
Yet other prior art devices are disclosed in U.S. Pat. No. 4,466,429 to Loscher et al. and U.S. Pat. No. 4,844,064 to Thimsen et al.
The foregoing discussion of the prior art derives from my earlier PCT Application No. WO 97/11646, which describes a hand-held surgical instrument for the cutting, removal, and storage of bone surface shavings for use as autogenous bone grafts. The instrument is comprised of a blade mounted in a handle for holding and supporting said blade. The blade has a cutting structure adjacent its distal end. In a preferred form, the handle cooperates to provide a storage space adjacent the distal end of the blade for receiving harvested bone from the cutting structure. The instrument is held at an acute angle to the bone, and with minimal downward pressure, is drawn across the bone surface to cut and collect a thin shaving of bone. The blade is preferably retractable to allow the clinician access to harvested material. A plunger preferably is incorporated into the handle to serve both as a locking mechanism to secure the blade and as a means to advance and consolidate the bone in the distal aspect of the instrument.
The present invention provides enhanced functionality and reduced cost over the surgical instrument described in my aforesaid PCT Application No. WO 97/11646.
The invention is directed to a hand-held surgical instrument for the cutting, removal, and storage of bone surface shavings for use as autogenous bone grafts. The instrument is comprised of a blade and storage compartment coupled to a handle. The blade may be made from a section of metal that is oriented relative to a longitudinal axis of the handle to allow the operator to more easily cut or scrape and accumulate bone. The blade preferably is slid into place over a collection chamber and secured to prevent accidental removal. The collection chamber includes storage space adjacent the cutting edge of the blade for receiving harvested bone from the blade. The collection chamber may be coupled to a handle portion at a joint. The joint allows the user to orient the blade relative to the handle in order to access hard to reach locations. A pry bar may be employed to assist in removal of the blade from the collection chamber. The pry bar may be stored within the handle portion.
In use, the blade and collection chamber is held at an acute angle to the bone and the user applies a minimal downward pressure as the tool is drawn across the bone surface. Thin shavings of bone are cut by the cutting edge and collected in the collection chamber. The clinician can view the amount of harvested material through an opening, preferably a slot, provided in the blade.
In a preferred embodiment, the blade is removable and replaceable, while the handle is reusable.
In another preferred embodiment of the invention, the handle has an area of reduced mechanical strength or a flexible joint displaced from the cutting edge, the area of reduced mechanical strength allowing the cutting edge to be angularly positioned relative to a longitudinal axis of the blade.
The above and other objects, features, and advantages of the present invention will be apparent in the following detailed description thereof when read in conjunction with the appended drawings wherein the same reference numerals denote the same or similar parts, and wherein: